Well I just leave them at room temps of about 20-25c and they hatch in like 7-21 days.
And Jan no they do not fly away, they cant fly actualy what the females do is just move from the cacoon and sit there and the males are going hay wire trying to find a mate!
What you should try do to make it easier for your self is to hatch them in them seperately because sometimes if they hatch together the male might find the female on the cacoon and start mating there and then the female might also lay the eggs on the cacoon so it makes it a mission.
Good luck